robots.net blog for slap.fishhttp://robots.net/person/slap.fish/
robots.net blog for slap.fishen-usmod_virguleSun, 2 Aug 2015 18:24:32 GMTWed, 28 Feb 2007 10:47:40 GMT28 Feb 2007http://robots.net/person/slap.fish/diary.html?start=7
http://robots.net/person/slap.fish/diary.html?start=7Steady progress on 48k's electronics - the card cage
backplane is mechanically complete, and partially wired -
and I now have 3 of the cards complete.
<p> <p> The first is a PSU/standby/timer card, which has two
MCUs -
this will monitor the PSU voltages and create recharge
requests to the main CPU, and oversee the recharging once
the robot has 'docked' and the main CPU relinquished
control and the robot powered down (standby mode).
<p> <p> The second complete card is the MCU for handling the
compressed air supply - a deceptively complex task. The
problem with an on-board compressor is the large surge of
power required to start it when the reservoir is already
pressurised - there are two air valves which need to be
carefully controlled, as well as the main compressor motor.
I thought this would be a simple card to program.. wrong!
<p> <p> Third up is the card (containing 4 MCUs) which will
handle
the steering and drive motor controls - lots of quadrature
encoders to keep track of, but ultimately an exercise in
position/speed control.
<p> <p> Did get some time to do some initial experiments with
I2C
communications - and although it's a little more software
intensive with PICs than I'd anticipated, it'll do the job
of providing a main communication channel between all the
cards quite well.
<p> <p> ..still plenty to do before I can really get down to
properely programming it all though.
<p> <p> - My lathe is now up and running again, upgraded with a
3
phase motor + inverter instead of the unreliable standard
DC motor (burnt out the second one before xmas). As any
machinist knows, small Chinese metalworking tools are good
value - but don't ever rely for heavy use - at least until
you've 'debugged' them and made improvements.. my little
7x12
has had many hours spent on it (a project in itself), and
is quite literally a different machine. I've a few changes
to the mill in mind as well!
I tested out the new motor making up some parts for my
fathers model R/C boat that I offered to install the
motor/R/C equipment etc. into - no shortage of power now.
The soft start is useful as well - but sadly, games
of 'dodge the chuck key' are no longer possible - it just
falls out safely instead of hurtling at your head like an
enraged 5 ounce metal wasp that's smelt your ice cream. I
feel I can live without that though.
<p> <p> Back onto robotics now - A Boebot joined the throng of
projects competing for spare time. This is my first
experience of the Basic Stamp (version 2), and I must say
I'm really impressed me with the speed and ease with which
you can have it doing some clever stuff. I liked it so much
I've now got a second one to experiment with. They're very
difficult to beat in terms of ease of use - and it's nice
to be able to play around and get real results quickly..
something that programming PICs in ASM definitely isn't.Wed, 3 Jan 2007 16:52:24 GMT3 Jan 2007http://robots.net/person/slap.fish/diary.html?start=6
http://robots.net/person/slap.fish/diary.html?start=6A new year, and things are gathering momentum.
<p> Since the last entry, I've been working on the pneumatic
compressor controller, and the first of the MCUs which has
the task of overseeing the system power/recharge strategy -
as well as some smaller functions which I've grouped
together as it will have it's own standby PSU - like system
clock/standby/hibernation modes, and a few others.
<p> I've been developing using Microchip 16F876 devices and an
ICD2 clone under MPLAB/Assembler - and so far this
combination is perfectly suited to the lower level MCUs, so
I'll probably be staying with this setup for most of the
first layer - the pneumatics, drive and steering - and all
of the associated encoders and other feedback are all
doable, it seems - and importantly, I2C communications to
the next layer in the heirarchy are supported also.
<p> Other parts like the card cage/backplane, and battery power
distribution are coming together.
<p> In other news, I've also added another robot arm to the
menagerie - a UMI RTX just like this one:
<p> http://users.telenet.be/emlab/Foto's/rtx2.jpg
<p> I've had it moving and knocking things off shelves using
RS232 - and writing some more code that has it doing
something a little more constructive is a future project. A
nice task for it would be waiting at the recharge outlet
for when 48k needs a top-up, and having the arm wake up and
plug in the charger sounds like a good challenge in robot
cooperation - which is another area of interest.
Fri, 6 Oct 2006 10:54:48 GMT6 Oct 2006http://robots.net/person/slap.fish/diary.html?start=5
http://robots.net/person/slap.fish/diary.html?start=5Ok, no stories about house decorating this time, I promise.
<p> <p> I've actually just aquired a working robot arm - a
Teachmover, like so:
http://www.questechzone.com/microbot/teachmover.htm
<p> <p> It's one of those classic stepper/cable driven arms,
popular with universities etc. No manual, but the teach
pendant is easy to use, and after a little googling, I had
it repeating sequences quite quickly - I have some partial
information on the RS232 interface commands, but if anyone
else reading has experience with one of these, or any any
information, I'd be interested to hear from you!
<p> <p> It joins the other arm I have - a slightly larger TQ
MA2000
aka 'The Open University Robot' - which is in need of a new
controller and some mechanical attention (needs new wrist
servos and a replacement gripper, as the old one was
pneumatic only), as I bought it non-functional - that's
currently packed away, as a future project.
<p> <p> Anyway, it's a neatly put together little arm that has
the
features of more serious 'proper' arms that cost 10 times
as much, and a big step up from those battery powered toys
and kits you can get that strain under their own weight and
wobble around when you sneeze in the next room. Surpisingly
rigid, and can pick up a few ounces without a problem.
Quite apart from the fact I enjoy mucking around with this
kind of stuff anyway, I got it (and the other TQ arm), to
study and help give me some ideas (and hopefully avoid any
pitfalls) for designing the arm for 48k - which will be a
far larger and more serious piece of kit, and which I want
to get right, first time - considering the time and money
involved.
Mon, 11 Sep 2006 13:27:00 GMT11 Sep 2006http://robots.net/person/slap.fish/diary.html?start=4
http://robots.net/person/slap.fish/diary.html?start=4It was my daughters sixth birthday party yesterday - and
foolishly, we 'threw' it at home.. haha. Anyone who's ever
had a kids party at their own house, grimace.... now;
Solidarity, brother.
<p> In the second half - after all the kids were fuelled up
with sugar - and I was the object of some collective
vengence I couldn't quite understand or manage to escape
from (just being in the garden was enough, I suspect), I
inadvisedly played the 'Team Monster' part too well - and
our neighbours son (same age) played his Action Man
character perfectly - and felled me with a left hook to the
unmentionables, bless him.
Whilst in the recovery position - our other neighbours
daughter, one year younger - yelled 'kick him in the
goolies!!' - and although I thought this was commendable,
and in the party spirit, thought it was rather out of
character for a fairy. She did make me a cup of 'monster
tea' whilst I recuperated in the 'dungeon' though, nice one
Hollie. Anyway.. you get the general idea - feigning
immobility (actually that bit was for real), sleep, or
death, did no good - and after 45 minutes of that I felt
like a Pinata... I'm sure this tradition was invented after
parents realised if the kids had something else to beat up
on, they could avoid all that awkward writhing around in
agony - damn fine idea if you ask me. In England we're not
so clever, see - plus the mere suggestion of a hitting a
paper mache donkey with sticks would bring down the wrath
of a small army of little people upon us, kids here seem to
prefer a live target that they can get groans of pain out.
Next year I'll hire a clown for them to beat up, and
somewhere that isn't our house for them to beat it up in -
mostly for reasons of forensic evidence.
<p> Talking of the the house - it is finally finished.
<p> Wow.. Still can't quite believe it myself - 4 months it's
taken, and if I live to never see another plasterboard
screw, or half a bag of cement et cetera (it's a looong
list) - I'll be happy.
<p> This week, I will mostly be working on getting a pretty
good pathalogical hatred of painting going - I
conservatively started at 'dislike' - and after approx 16
cummulative hours so far, I've already got my teeth
grinders merit badge - yay me.
<p> I estimate another 100 hours or so to go - after which
Defcon 1 will be long gone and I'll be continuously mashing
the big red button, oooh yes. My only relief will be
screaming 'Paaaint... Bruuush!!' at Jehovas Witnesses when
they come round at Xmas for their annual attempt at
explaining how, in fact - I've actually got it all wrong.
This year I've cancelled Richard Dawkins, and decided to
argue in the style of an enraged decorator you see - and
although right now it seems a fair way off, when the time
comes I'm gonna do this particular idiom with feeling, and
possibly with bells on (no really - they hate that drunken
seasonal stuff).
<p> Enough of that, anyway - you probably want to know
something more Robot-related ? Well, 48k is still in the
garage - although now looking more like it (rightfully)
owns it - rather than merely happening to be also in it -
as was the case up until recently, what with all the other
stuff being stored in there. Some of the kids (see above)
were suitably impressed, even though it didn't look like
a 'real' robot (False Maria has a lot to answer for). I
have a lot of getting up to speed to do - the lathe and
mill in the shed need a freshen up after their time off -
not that there's much more metalwork to be done, hopefully.
What's nice though, is that after a long break, looking
closely again at it - I get a rush of enthusiasm to think
of how I've designed &amp; built this thing - and can't wait to
crack on once again, checking up on Robots.net once in
awhile during the summer has helped keep the creative
engine idling, and now it's raring to go again.
<p> Actually, talking of robots - I think there is a niche for
kids birthdays.. like these security droids that roam banks
at night or something. Tactical support for childrens
entertainers would be welcome, don't you think ? I see
there is some consideration for lightly arming security
robots, though I think that would be inappropriate for a
kids party - as they'd need to be *definitely* armed.Thu, 6 Jul 2006 14:23:25 GMT6 Jul 2006http://robots.net/person/slap.fish/diary.html?start=3
http://robots.net/person/slap.fish/diary.html?start=3not much progress on 48k for awhile - I'm in the midst of
major house renovation/extensions, which, amongst other
things, means that every scrap of storage space is packed
full of boxes - including the spare rooms.. one of which
will become the new workroom, and doubtless will be the
last I'm allowed to finish and get my bench and equipment
set back up again.. woe..
<p> still.. despite all the moving around, 48k has stayed on
it's stand in the garage like the very heavy, very
complicated looking, shiny, and extremely dangerous if
fallen on by thing that it is.. like it's somehow immune to
the chaos going on around - which seems somehow gratifying.
<p> During the course of the work on the house - every single
builder, carpenter, bricklayer, plumber, electrician,
apprentice thereof and general gawker has asked the same
questions, in the same order - without fail.
<p> What is it ?
What does it do ?
<p> Despite giving quite a few different variations on the same
general theme(s) that qualify for answers (remote control
robot, robot for retrieving small objects, robot for roving
around autonomously, robot for throttling neighbourhood
cats that dare to defocate under the rhododendrons, robot
for world domination as long as there are no steps etc.) -
I know they all think I'm not quite all there.. in the
nicest possible sense of course - though I've noticed they
do scrutinise free cups of tea just a little more closely
afterwards.. hmmm. There is often a third question (perhaps
optional ?) - which is 'So what do *you* do ?' - I'm not
quite sure I ought to wonder too hard on why they ask that
one.
<p> anyway.. in another month or so I may be able (allowed?) to
get back to it - does anyone know the typical ultrasound
signature of the average un-house-trained cat ?Wed, 1 Mar 2006 10:50:03 GMT1 Mar 2006http://robots.net/person/slap.fish/diary.html?start=2
http://robots.net/person/slap.fish/diary.html?start=2I promised a more up to date picture of 48k - so:
<p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p>
<a href="http://homepage.ntlworld.com/retro.spect1/rob10.JPG"
> latest pic </a>
<p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> It's in
a
somewhat 'stripped'
state
at
the
moment -
the
arm
base joint, batteries, and electronics housings are
missing - but it shows the mechanical layout clearer.
<p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> There
is
very
little in
the
way
of
actual
control
elements
in place yet - but I thought people might appreciate seeing
a bit more of what's involved in the actual mechanics, as
this is an area often overlooked. I for one like to see how
something works under the skin.. a robots 'bones' if you
like - the hardware solution is just as interesting to me
as the software.
<p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> a
couple
more,
showing
some
details:
<p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p>
<a href="http://homepage.ntlworld.com/retro.spect1/rob11.JPG"
> drivetrain</a>
<a href="http://homepage.ntlworld.com/retro.spect1/rob12.JPG"
> suspension</a>
<p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> ---
<p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> <p> I will
be
remounting
the
arm
base
joint
and
batteries
soon -
and then onto connecting up the pneumatics.. then it'll be
on it's wheels and under power for the first time sometime
soon [rubs hands and laughs like Vincent Price].
<p> <p> <p> <p> <p> <p> Wed, 15 Feb 2006 11:30:29 GMT15 Feb 2006http://robots.net/person/slap.fish/diary.html?start=1
http://robots.net/person/slap.fish/diary.html?start=1Some background on 48k - here are a few pics showing a
somewhat disjointed progression of the build:
<p> http://homepage.ntlworld.com/retro.spect1/robot.JPG
http://homepage.ntlworld.com/retro.spect1/rob1.jpg
http://homepage.ntlworld.com/retro.spect1/rob2.jpg
http://homepage.ntlworld.com/retro.spect1/rob6.jpg
http://homepage.ntlworld.com/retro.spect1/rob7.jpg
http://homepage.ntlworld.com/retro.spect1/rob8.jpg
http://homepage.ntlworld.com/retro.spect1/rob9.JPG
<p> You can see that early on, I'd planned on driving the
wheels via differentials and a single motor - that was
changed in favour of a gearhead motor per wheel, arranged
to drive the wheels directly (via couplings). Most
recently, I have altered the drive arrangements again to a
belt system, which means the drive train now has some
allowance for slip built it, and any shock torques are
unlikely to damage the gearheads - an extra 2:1 was used as
it was looking increasingly likely that climbing a 15
degree incline was going to be close to exceeding the
motors capabilities.
<p> Last night I had the first wheel under power, using the new
layout, and it works great - another added benefit of belt
drive is I can quickly disengage the tensioner, effectively
disconnecting drive, and allowing a freewheel mode - which
I'm sure will come in useful when it's finally out and
about, and I need to tow it home on a rope - picking it up
will not be an option! Thu, 9 Feb 2006 10:48:04 GMT9 Feb 2006http://robots.net/person/slap.fish/diary.html?start=0
http://robots.net/person/slap.fish/diary.html?start=0Well, 'Hello World'... I've been regularly checking up on
Robots net for a couple of years now - but have finally
motivated myself into joining.
<p> I am currently working on this:
<p> http://homepage.ntlworld.com/retro.spect1/rob9.JPG
<p> This picture is a little old now, and I will endevour to
get something more up to date on my site soon.
<p> It is (will be) an autonomous Rover - as you can see it is
no small undertaking, and the project is in it's 3rd year,
I will add it to the list of robots when I feel it
qualifies - for now, I am still tinkering with the
mechanics, and getting them just right, before I set it
down and get out the way (it will be in excess of 100kgs
when fully built).. a Rover shaped hole in the wall is a
distinct possibility in the future - not to mention me
running down the road frantically warning people out the
way.
<p> Excuse my irreverence.. it IS a serious project - I,
however, am constrained otherwise as, being only a hobby -
it is the only way to remain sane. How else does one keep
smiling, night after night in the shed - setting titanium
turnings alight and picking aluminium swarf from surprising
places ?
<p> By the way - the large assembly torward the front is the
base joint for a substantial arm, which I have
provisionally pegged at a 5kg payload, fully extended
(approx 1 meter)